As integrated circuits become more dense, often containing hundreds of I/O connections, existing techniques of packaging, such as using lead frames for the I/O connections, become less suitable. Packaging is considered by many in the industry to be the pacing technology for integrated circuit development. Many designers have recognized the need for developing chip carriers which do not require the deposition of high resolution, metallized traces on the chip carriers, while still allowing the ICs to be hermetically sealed. However, creating such a chip carrier has presented significant manufacturing problems.
In one solution to provide hermetic sealing, chip carriers are fabricated using substrates onto which metallized traces are placed to provide electrical connections from the periphery of the substrate to the integrated circuit packaged within. A lid is then bonded to the substrate and over the metallized traces to provide a hermetic seal. One example of this technique can be found in the co-pending and commonly assigned application filed Apr. 25, 1989, Ser. No. 07/343,506 by Steitz et al. entitled "METALLIZED CERAMIC CHIP CARRIERS", which is incorporated herein by reference. Another example can be found in the co-pending and commonly assigned application filed June 15, 1989, Ser. No. 07/366,604 by Neumann et al. entitled "CHIP CARRIER WITH TERMINATING RESISTIVE ELEMENTS", which is incorporated herein by reference.
In the existing art, it is not possible to connect the IC directly to the circuit board using a direct connection means for hundreds of I/O connections while at the same time allowing hermetic sealing of the IC. The primary shortcomings in the existing art are its expense, due to the high cost of the metallization process, and its reduced reliability, due to the high number of intermediate connections and parts. Thus, there is a need in the art for a chip carrier which does not require the deposition of metallized traces onto the carrier substrate but allows the integrated circuit to be hermetically sealed and directly connected to a circuit board.